The rough endoplasmic reticulum (also known as the microsome fraction) is involved in the synthesis of certain proteins. Not all cellular proteins are synthesized on the RER. To understand which proteins are, and are not, synthesized on the RER you should understand the relationship between the RER and the endomembrane system of the cell.
Proteins that are synthesized on the RER
The proteins that are synthesized on the RER are, in general, those that will be secreted, be sent to the lysosome or other intracellular organelles that are a part of the endomembrane system, or become part of the plasma membrane (integral membrane proteins.
Proteins that are not synthesized on the RER
A few of the proteins that are not syntheized on the RER include many that are found in the mitochondria, those of the glycolytic pathway and many cytoseleton proteins.
More detailed review of mechanism of proteins synthesis .